Now, don’t go hating on Twitter or trying to, you know, make people bust heads. Twitter has many, many great uses. It’s great for breaking real-time sort of news, it’s fantastic for asking your friends. Google, on the other hand, we try to return really reliable, really reputable information. So, if you’re sorting by date, Twitter is fantastic. If you want an answer to a question that’s been around for a while, Google’s great for that.
If you don’t have as many friends, then you might not be able to get the questions that you want answered on Twitter. And I wouldn’t be surprised if spammers eventually see traffic on Twitter and they’re like, “Mwahahahaha.” Because if you’re only sorting by date, then any new fad that comes along, the spammers might try to jump onto that. So, they’re different. They’re good for different things. I would say use whatever works best for you.
by Matt Cutts - Google's Head of Search Quality Team